The present invention relates to a compact fluorescent lamp and a self-ballasted fluorescent lamp which are made to an even smaller scale, and also relates to a luminaire.
Examples of conventionally known self-ballasted fluorescent lamps include a self-ballasted fluorescent lamp which is provided with a cover, a lighting circuit contained in the cover, and an arc tube bent or otherwise formed into an appropriate shape and contained in a globe, said cover having a base that can be mounted in a socket designed for a typical light bulb.
A self-ballasted fluorescent lamp commercially available at present typically has such specifications as a height of approximately 130 mm (including the height of the base), an outer diameter of approximately 70 mm, an outer tube diameter of the arc tube of approximately 12 mm, a discharge path length of approximately 280 mm, a tube wall thickness of not less than 1.1 mm, and a lamp power of approximately 13 W. Due to its configuration, however, it is difficult to provide a fluorescent lamp which has such an arc tube and is as compact as typical light bulb. Nevertheless, there is an increasing demand for fluorescent lamps made to an even smaller scale.
Another example of self-ballasted fluorescent lamps is disclosed in Japanese Patent Laid-open No. 1987-12051, which relates to a fluorescent lamp, wherein an arc tube having three U-shaped bent bulbs is disposed in such a way that the three U-shaped bent bulbs respectively correspond to the three sides of an approximately equilateral triangle. However, as there is no detailed discussion in the above Japanese Patent Public Disclosure as to various criteria regarding the reduction of the dimensions of the lamp, such as dimensions and the shape of the arc tube as well as criteria for lighting the lamp, the invention disclosed in said publication does not provide the optimum configuration for reducing the dimensions of the lamp.
Another example of fluorescent lamps is disclosed in Japanese Patent Laid-open No. 1987-12051, wherein the arc tube of the fluorescent lamp is formed in a U-like shape having corners bent at approximately 90xc2x0. However, the configuration having such an arc tube, i.e. an arc tube having sharp corners, presents a problem of irregularity in luminance, because the corners of the arc tube are too close to the globe when the arc tube is contained in the globe which is as small as that of a typical light bulb.
Another example of fluorescent lamps is disclosed in Japanese Patent Laid-open No. 1997-69309, wherein the arc tube is bent into a spiral or other shape so as to produce a lamp having a shape and dimensions nearly identical to those of a typical light bulb. However, a configuration which calls for bending the arc tube into such a complicated shape as a spiral requires a complicated production process and presents a problem in that reduction of production costs is difficult. As it is difficult to put such an arc tube in practical use for reasons described above, an arc tube having U-shaped bent bulbs is normally used. However, a lamp having such an arc tube, too, is difficult to be made compact, because it imposes various limitations in the shape and the dimensions of the U-shaped bent bulbs.
When the dimensions of a fluorescent lamp are reduced, there arises the danger of heat from the arc tube exerting an unfavorable influence on the lighting circuit that is contained in the cover. As a fluorescent lamp disclosed in Japanese Patent Laid-open No. 1996-273615, one of the known ways to solve this problem is a configuration which calls for disposing a circuit board for mounting components of the lighting circuit thereon in such a manner that the components are positioned apart from the ends of the arc tube at which the electrodes are provided. As a result of the reduction of the dimensions of fluorescent lamps, however, circuit boards, too, are made compact. Therefore, the above configuration presents a problem in that the reduction in the space in which the necessary components are mounted increases the planar dimensions of the lamp too much, particularly at the part where the cover is located.
Regarding a self-ballasted fluorescent lamp which is provided with a cover having a base that can be mounted in a socket designed for an incandescent lamp, a lighting circuit contained in the cover, and an arc tube bent or otherwise formed into an appropriate shape and contained in a globe, a configuration which calls for disposing a circuit board at the base-facing end of an arc tube that is bent in a U-like shape and arranging electrical components on both end of the circuit board is widely known. One of examples of such configuration is disclosed in Japanese Patent Laid-open No. 1988-245803. Compared with the aforementioned configuration which calls for positioning the circuit board apart from the ends of the arc tube, said configuration disclosed in Japanese Patent Laid-open No. 1988-245803 is more effective in reducing the horizontal dimensions of the lamp at the region of the cover. On the other hand, it presents such problems that interference between the electrical components and the arc tube, especially between the electrical components and the end of the arc tube, increase the influence of heat exerted on the electrical components and that such a configuration makes the lamp too long.
As described above, the outer diameter of the conventional self-ballasted fluorescent lamp is larger than the outer diameter of typical light bulb. Therefore, this configuration presents problem in that it is not suitable for a luminaire which uses a typical light bulb in place of a typical light bulb.
Regarding a fluorescent lamp which is used to a self-ballasted fluorescent lamp, a configuration which a bulb has a bent discharge path, which formed by connecting a three U-shaped tubular bodies in series and electrodes disposed at the both ends of the bulb is widely known. One of examples of such configuration is disclosed in Japanese Patent Laid-open No. 220360-1989. And such configuration ensures the length of a discharge path and the reduction of the dimensions of a fluorescent lamp.
In some cases, such a fluorescent lamp uses a main amalgam for controlling the pressure of the mercury vapor in the bulb within an appropriate range during the time that the lamp is lit under normal conditions and an auxiliary amalgam for absorbing mercury floating in the bulb when the lamp is turned off and releasing the absorbed mercury during the early stage of lighting, including the moment when the lighting is initiated. In a configuration where the amalgams are used, the main amalgam is contained in a minute tube which serves to discharge the air and projects from an end, i.e. the end at which an electrode is contained in the bulb, of a tubular body that is located at an end of the bulb, while the auxiliary amalgam is disposed at an end of a tubular body positioned at the middle portion of the bulb. However, when the exhaust minute tube that contains the main amalgam and projects from a tubular body situated at an end of the bulb is located at the same end at which an electrode enclosed in the bulb is located, the temperature of the main amalgam becomes too high due to the influence of the heat from the electrode. Such an increase in the temperature of the main amalgam impairs the effective control of the pressure of the mercury vapor and causes the pressure of the mercury vapor to increase too much, resulting in a decrease in luminous flux. This configuration presents another problem in that it is difficult to uniform or stabilize the pressure of the mercury vapor in the tubular body that is located at the other end of the bulb, at a long distance from the main amalgam.
Another example of fluorescent lamps characterized by inclusion of a main amalgam is disclosed in Japanese Utility Model Publication No. 1992-47893, wherein a main amalgam is disposed in a minute tube projecting from an end of one of the three tubular bodies that form the bulb, said tubular body being the middle tubular body of the three tubular bodies. The fluorescent lamp having this configuration is capable of reducing the influence of the heat from the electrodes exerted on the main amalgam, limiting the pressure of the mercury vapor within an appropriate range by preventing an excessive increase in temperature of the main amalgam, and also capable of reducing the distances from the main amalgam to the respective ends of the bulb by a nearly identical degree, thereby making the pressure of the mercury vapor uniform and stable throughout the interior of the bulb. On the other hand, the above configuration presents a problem in that disposing the main amalgam in the minute tube projecting from an end of the middle tubular body of the three tubular bodies of the bulb positions the main amalgam too far from the electrodes, making it difficult to warm the main amalgam. Especially at the initiation of lighting, when both the ambient temperature around the fluorescent lamp and the temperature of the main amalgam itself are low, the main amalgam is slow to release mercury, because it takes a long time for the temperature of the main amalgam to reach the level where the main amalgam functions most effectively. As a result, the luminous flux build-up characteristics become poor, and it takes an excessively long time to stabilize the luminous flux.
In response to the recent tendency toward compact fluorescent lamps, the demands for reduction of the dimensions of bulbs are on the increase. In the configuration where each minute tube for discharging the air is provided at an end of the bulb, the reduction of the diameter of the bulb makes it necessary to reduce the diameter of the minute tubes. However, a minute tube having a diameter smaller than a given dimension has poor exhaust conductance, resulting in decrease in the exhaust efficiency. On the other hand, if the diameter of the minute tubes are not reduced, the distance between each minute tube and a pair of inner copper-weld wires that support an electrode is reduced, making the operation of sealing the bulb difficult.
In order to solve the above problems, an object of the present invention is to provide a fluorescent lamp and a self-ballasted fluorescent lamp that are characterized by the minute tubes positioned so as to permit the amalgams to be disposed at the optimum locations and enable the reduction of the diameter of the bulb. Another object of the present invention is to provide a self-ballasted fluorescent lamp and a luminaire that enable the reduction of the diameter of the portion near the base of the lamp as well as the reduction of the length of the lamp. Yet another object of the present invention is to provide a compact self-ballasted fluorescent lamp which is equivalent to a typical light bulb and a luminaire including such a self-ballasted fluorescent lamp.
A fluorescent lamp according to the present invention includes a bulb having a bent discharge path, which is formed by connecting a plurality of tubular bodies in series, and a plurality of minute tubes located at the middle of the discharge path and communicating therewith; a phosphor applied to the inner surface of the bulb; filler gas hermetically contained in the bulb; electrodes respectively disposed at the two ends of the bulb in such a manner as to be enclosed in the sealed bulb; and an amalgam enclosed in a minute tube closest to either electrode. By enclosing the amalgam in a minute tube which is, of the plurality of minute tubes provided at the middle portion of the bulb, located closest to either electrode, the configuration described above prevents the influence of the heat from the electrode from increasing the temperature of the amalgam too much and also permits the amalgam to be warmed easily during the initial stage of lighting. As a result, the configuration is capable of maintaining the pressure of the mercury vapor within an appropriate range and reducing the time taken for the luminous flux to become stable when lighting is initiated.
According to another feature of the invention, the fluorescent lamp has the same configuration as described above except that one of the electrodes attached to the two ends of the bulb so as to be contained in the sealed bulb is a preheating-side electrode, i.e. an electrode disposed at the end where preheating is conducted, while the other electrode is a non-preheating-side electrode, i.e. an electrode disposed at the end where preheating is not conducted; and that the amalgam is enclosed in the minute tube which is closest to the preheating-side electrode. As a result, this configuration permits the amalgam to be warmed easily during the initial stage of lighting and also improves the build-up characteristics of luminous flux.
In the configuration of a fluorescent lamp described above, by forming the open end portion through which said minute tube communicates with the corresponding tubular body narrower than the interior of the body of the minute tube, in which an amalgam will be enclosed, reliable enclosure of the amalgam is ensured.
According to yet another feature of the invention, a fluorescent lamp includes a bulb having an inner tube diameter ranging from 6 to 9 mm and a bent discharge path, which is formed by connecting a plurality of tubular bodies in series, each tubular body that is located at an end of the bulb being provided with a minute tube formed at the non-electrode end of the tubular body, i.e. the end where an electrode is not disposed; a phosphor applied to the inner surface of the bulb; filler gas hermetically contained in the bulb; and electrodes respectively disposed at the two ends of the bulb in such a manner as to be enclosed in the sealed bulb. By forming minute tubes for discharging the air at the non-electrode ends of the respective tubular bodies located at the two ends of the bulb, the configuration described above enables a slender bulb with an inner tube diameter ranging from 6 to 9 mm to have a minute tube having a diameter not smaller than a given dimension as well as superior exhaust conductance and exhaust efficiency at the non-electrode ends of the respective tubular bodies located at the two ends of the bulb. At the same time, the above configuration facilitates an operation to dispose electrodes at the electrode-ends of the tubular bodies and seal the bulb.
In the configuration of a fluorescent lamp that has the same configuration as the one described above, by enclosing an amalgam in the minute tube that is provided at the nonelectrode end of a tubular body located at an end of the bulb, it is possible to prevent the influence of the beat from the electrode from increasing the temperature of the amalgam too much and also permit the amalgam to be warmed easily during the initial stage of lighting. As a result, it is possible to maintain the pressure of the mercury vapor within an appropriate range and reduce the time taken for the luminous flux to become stable when lighting is initiated.
In the configuration of a fluorescent lamp that has the same configuration as the one described above, by disposing an auxiliary amalgam in the bulb, it is possible to maintain the pressure of the mercury vapor within an appropriate range and reduce the time taken for the luminous flux to become stable when lighting is initiated.
In the configuration of a fluorescent lamp that has the same configuration as the one described above, by positioning the tubular bodies of the bulb in such a manner that the tubular bodies respectively correspond to the three sides of a triangle when viewed in a cross section, the bulb can be made into such a compact shape as to be usable as a compact self-ballasted fluorescent lamp or the like.
A self-ballasted fluorescent lamp according to the present invention includes a fluorescent lamp and a lighting device for lighting the fluorescent lamp, said fluorescent lamp having a configuration corresponding to any one of the configurations described above. This feature of the invention is capable of providing a self-ballasted fluorescent lamp which has the same effect as one of the fluorescent lamps described above.
A self-ballasted fluorescent lamp according to the present invention includes an arc tube which is formed by parallely arranging a plurality of U-shaped bent bulbs having an inner tube diameter ranging from 6 to 9 mm in such a manner that the height of the bulb and the length of the discharge path respectively range from 50 to 60 mm and from 200 to 300 mm and that the lamp has a total luminous flux of not less than 700 lm and a lamp efficiency of not less than 60 lm/W when the lamp is lit at the lamp power of 7 to 15 W; an envelope having a cover that includes a base and is adapted to permit said arc tube to be attached thereto, the height of the envelope ranging from 110 to 125 mm including the height of the base; and a lighting circuit contained in the cover. As this configuration includes said arc tube, which is formed by parallely arranging a plurality of U-shaped bent bulbs having an inner tube diameter ranging from 6 to 9 mm in such a manner that the height of the bulb and the length of the discharge path respectively range from 50 to 60 mm and from 200 to 300 mm and that the lamp has a total luminous flux of not less than 700 lm and a lamp efficiency of not less than 60 lm/W when the lamp is lit at the lamp power of 7 to 15 W, and limits the height the envelope, which is provided with a cover including a base to which the arc tube is attached, in the range from 110 to 125 mm, it is possible to determine the optimum criteria for the components to make the dimensions and the total luminous flux of the lamp correspond to those of a typical light bulb for general illumination, such as an incandescent lamp having a rated power of 60 W type. The lower limit of the inner tube diameter of the tube is set at 6 mm as mentioned above, because the tube having an inner tube diameter of less than 6 mm requires a considerably high starting voltage at and is therefore impractical. The term xe2x80x98a total luminous fluxxe2x80x99 mentioned above refers to a value representing radiation from an entire self-ballasted fluorescent lamp. Therefore, if the self-ballasted fluorescent lamp includes a globe, it represents the result of a measurement conducted in the state where the globe is attached. Furthermore, xe2x80x98a lamp efficiencyxe2x80x99 is defined as a value based on the lamp power minus the power consumption of the lighting circuit.
According to yet another feature of the invention, a self-ballasted fluorescent lamp includes an arc tube formed by parallely arranging a plurality of U-shaped bent bulbs, each of which has an outer tube diameter ranging from 8 to 11 mm, a tube wall thickness ranging from 0.7 to 1.0 mm and a smoothly curved crown; a cover including a base that is adapted to permit said arc tube to be attached thereto; and a lighting circuit contained in the cover. As this configuration includes said arc tube formed by parallely arranging a plurality of U-shaped bent bulbs, each of which has an outer tube diameter ranging from 8 to 11 mm, a tube wall thickness ranging from 0.7 to 1.0 mm and a smoothly curved crown, it is possible to determine such a tube diameter as to make the dimensions and the total luminous flux of the lamp correspond to those of a typical light bulb for general illumination, such as an incandescent lamp having a rated power of 60 W type and also determine such a range of the thickness of the bulb wall as to enable the increase of the inner surface area of the bulb while ensuring sufficient strength within the limit of the outer diameter of the bulb determined as above. Further, in order to form each U-shaped bent bulb within the limit of the tube wall thickness determined as above, the crown of the U has to be smoothly curved. Should the crown have a sharp corner or corners, the tube wall at the corner(s) would be too thin to maintain sufficient strength.
According to yet another feature of the invention, a self-ballasted fluorescent lamp includes an arc tube formed by parallely arranging a plurality of U-shaped bent bulbs, each of which has a bent portion and straight portions; a cover including a base that is adapted to permit said arc tube to be attached thereto; and a lighting circuit which includes a circuit board having the maximum width ranging up to 1.2 times the maximum width of the arc tube, the maximum width of the arc tube being the dimension along which the U-shaped bent bulbs are arranged, said lighting circuit contained in the cover in such a manner that the circuit board is positioned with one of its sides facing all the ends of the straight portions of the arc tube and provided with components having relatively high heat resistance mounted on the side of the circuit board facing the arc tube and components having relatively low heat resistance mounted on the opposite side of the circuit board. According to the configuration as above, the maximum width of the circuit board is so set as to range up to 1.2 times the maximum dimension along which the U-shaped bent bulbs of the arc tube are arranged, and the components that have relatively high heat resistance are mounted on the arc tube facing side of the circuit board, while the components having relatively low heat resistance are mounted on the other side of the circuit board. Thus, the above configuration is capable of reducing the size of the circuit board while limiting the influence that heat exerts on the components mounted on the circuit board. Consequently, the configuration is capable of reducing the dimensions of the cover, which contains the circuit board, so that they are equivalent to the dimensions of a typical light bulb. Although it is recommended that the circuit board have a shape of a circular disk, which is the most effective shape to ensure the space for mounting, the circuit board may have a polygonal shape, such as a square, or an oval shape.
According to yet another feature of the invention, the components having relatively high heat resistance of the fluorescent lamp described above are chip-shaped rectifying devices. Therefore, the thermal influence from the arc tube can be limited.
According to yet another feature of the invention, a self-ballasted fluorescent lamp includes a cover having a base; a lighting circuit contained in the cover; a globe having a nearly identical shape as a typical light bulb and attached to the cover; and an arc tube which is contained in the globe and has three or more U-shaped bent bulbs, each of which has a smoothly curbed crown, the U-shaped bent bulbs connected to one another in series and arranged so that their crowns are aligned in a circle and face the inner surface of the globe and that the U-shaped bent bulbs are spaced apart at a distance not exceeding the outer diameter of each bulb. As the arc tube has three or more U-shaped bent bulbs which have smoothly curbed crowns, are connected to one another in series, and positioned apart from one another in such a manner that the distance between the bulbs does not exceed the outer diameter of each bulb and that their crowns are aligned in a circle and face the inner surface of the globe, this configuration makes it possible to dispose the arc tube in the globe that is formed in a compact shape resembling a typical light bulb. This configuration is also capable of providing more uniform luminosity and more effective illumination even if the arc tube is contained in such a compact globe.
According to yet another feature of the invention, a self-ballasted fluorescent lamp includes an arc tube formed by parallely arranging a plurality of U-shaped bent bulbs having an outer tube diameter ranging from 8 to 11 mm, the maximum width of the arc tube along which the U-shaped bent bulbs are arranged ranging from 32 to 43 mm; a cover including a base that is adapted to permit said arc tube to be attached thereto; a lighting circuit contained in the cover; and a globe having a maximum outer diameter limited in the range from 55 to 60 mm and attached to the cover with said arc tube enclosed in the globe in such a manner that A2 greater than A1xe2x89xa7A3, wherein Al represents the minimum distance between the globe and each crown of the arc tube, A2 the minimum distance between the maximum diameter portion of the globe and the arc tube, and A3 the minimum distance between the base end of the globe and the arc tube. As a self-ballasted fluorescent lamp includes an arc tube formed by parallely arranging a plurality of U-shaped bent bulbs having an outer tube diameter ranging from 8 to 11 mm, the maximum width of the arc tube along which the U-shaped bent bulbs are arranged ranging from 32 to 43 mm, and a globe having a maximum outer diameter limited in the range from 55 to 60 mm and attached to the cover with the arc tube enclosed in the globe in such a manner that A2 greater than A1xe2x89xa7A3, wherein A1 represents the minimum distance between the globe and each crown of the arc tube, A2 the minimum distance between the maximum diameter portion of the globe and the arc tube, and A3 the minimum distance between the base end of the globe and the arc tube, the feature of the invention described above enables the determination of the optimum criteria for luminous intensity distribution in the direction of the sides and the crown of the arc tube.
The above configuration increases the luminous intensity distributed in the direction of the base and is therefore particularly effective in bringing the characteristics of luminous intensity distribution of the lamp into close proximity to those of an incandescent lamp. As a result, the lamp can be illuminated as if it were an incandescent lamp and used for a luminaire that is designed for an incandescent lamp without giving any disagreeability.
As the outer diameter of the globe or the diameter of the portion of the cover where the base is located has to be limited to no larger than 45 mm in order to make the lamp resemble a typical light bulb and more suitable to be fitted in a luminaire that uses a typical light bulb, the upper limit of the maximum width of the arc tube along which the U-shaped bent bulbs are arranged is set at 43 mm, taking the clearance between the inner surface of the globe or the cover and the outer circumferential surface of the arc tube into consideration. In cases where a self-ballasted fluorescent lamp is installed in a luminaire designed for a typical light bulb, limiting the outer diameter of the globe or the diameter of the portion of the cover where the base is located to no larger than 45 mm presents such other benefits as ensuring a wide clearance between the lamp and the other components of the luminaire, thereby enabling the radiation under good conditions.
By setting A1 in the range from 2 to 8 mm, A2 in the range from 3 to 13 mm and A3 in the range from 2 to 8 mm in the configuration of the self-ballasted fluorescent lamp described above, the optimum criteria for distributing light toward the sides and the crown of the arc tube can be determined.
By forming the self-ballasted fluorescent lamp described above so as to have an outer shape resembling a typical light bulb for general illumination, the invention permits the lamp to be mounted in a luminaire designed for a typical light bulb, thereby expanding the range of usage. As the self-ballasted fluorescent lamp having an outer shape resembling a typical light bulb can be mounted in such a luminaire without giving any disagreeability, the invention is also capable of improving the appearance of the self-ballasted fluorescent lamp. The term xe2x80x98light bulb for general illuminationxe2x80x99 mentioned above means a light bulb defined as JIS Standard C 7501. In cases where a self-ballasted fluorescent lamp is provided with a globe, it is desirable that the shape of the outline of the globe be similar to the glass light bulb of a typical light bulb.
As yet another feature of the invention, bonding the arc tube, the globe and the supporting member supporting the arc tube of a self-ballasted fluorescent lamp having the configuration as above to one another by means of a bonding agent permits the heat to be efficiently radiated from the arc tube through the globe and also simplifies the structure, thereby enabling the reduction of the production costs.
Furthermore, by arranging the U-shaped bent bulbs of the arc tube of a self-ballasted fluorescent lamp having the configuration as above in such a manner that their cross sections give the appearance of a triangle, the arc tube can be arranged in a compact shape.
By setting the distance w1 between the two straight portions of each U-shaped bent bulb of a self-ballasted fluorescent lamp having the configuration as above to be nearly identical to the distance w2 between each straight portion of a U-shaped bent bulb and the U-shaped bent bulb that is adjacent to said straight portion, and respectively limiting the distances w1,w2 in the range from 1 to 5 mm, the arc tube can be arranged in a compact shape. Although the distances w1,w2 may be set at any desired dimensions on condition of being in the range from 1 to 5 mm, it is desirable for production reasons that they be in the range from 2 to 3 mm. Further, a distance that exceeds 5 mm may make it impossible to produce a compact lamp.
According to yet another feature of the invention, the lighting circuit of a self-ballasted fluorescent lamp having the configuration as above includes a half-bridge type inverter main circuit having at least a pair of transistors consisting of an N-channel transistor and a P-channel transistor, which are connected in series with each other to an input power supply and serve as the main switching element for generating a high frequency voltage; a ballast choke connected to the inverter main circuit so as to light the arc tube in stable conditions; and a control means which has a secondary winding magnetically connected to the ballast choke and shared by the N-channel transistor and the P-channel transistor so that the control means serves to control the transistors by means of the secondary winding. With the configuration as above, wherein the control means operates the N-channel transistor and the P-channel transistor, the invention enables the control of a plurality of transistors under different conditions based on output from a single control means, thereby simplifying the configuration of the circuit. By using a lighting circuit which requires only a minimal number of parts as described above, the dimensions of the self-ballasted fluorescent lamp can be further reduced.
According to yet another feature of the invention, a self-ballasted fluorescent lamp includes an arc tube; a cover having a base; and a lighting circuit that has a circuit board and electrical components mounted on both sides of the circuit board in such a manner that the circuit board is contained in the cover and faces the ends of the arc tube and that the electrical components mounted on the side facing the arc tube are so positioned as to not be aligned with the ends of the arc tube. By so positioning the circuit board as to face the ends of the arc tube and mounting electrical components on both sides of the circuit board, the configuration described above is capable of reducing the dimensions of the circuit board and, consequently, reducing the diameter of the portion of the lamp near the base. Furthermore, by so arranging electrical components mounted on the side facing the arc tube as to not be aligned with the ends of the arc tube, the configuration is capable of preventing interference of the arc tube with the electrical components, limiting the influence of the heat from the arc tube, and reducing the length of the lamp.
According to yet another feature of the invention, a self-ballasted fluorescent lamp includes an arc tube; a cover having a base; and a lighting circuit and a lighting circuit that has a circuit board and electrical components mounted on both sides of the circuit board in such a manner that the circuit board is contained in the cover and faces the ends of the arc tube and that the electrical components mounted on the side facing the arc tube are so positioned as to not be aligned with the minute tubes of the arc tube. By so positioning the circuit board as to face the ends of the arc tube and mounting electrical components on both sides of the circuit board, the configuration described above is capable of reducing the dimensions of the circuit board and, consequently, reducing the diameter of the portion near the base. Furthermore, by so arranging electrical components mounted on the side facing the arc tube as to not be aligned with the minute tubes of the arc tube, the configuration is capable of preventing interference of the minute tubes that project further from the arc tube with the electrical components, limiting the influence of the heat from the arc tube, and reducing the length of the lamp.
By forming a self-ballasted fluorescent lamp having the configuration described above in such a manner that the outer diameter of the circuit board is nearly identical to the inner diameter of the cover, the invention makes it possible to arrange components with the space inside the cover used to the full extent and, consequently, reduce the diameter of the portion near the base.
In the configuration of a self-ballasted fluorescent lamp described above, by positioning the electrical components mounted on the side facing the arc tube apart from the electrodes of the arc tube, the influence that the heat generated by the electrodes exerts on the electrical components can be limited.
A luminaire according to the invention is provided with a self-ballasted fluorescent lamp which has any one of the configurations described above. Using a compact self-ballasted fluorescent lamp according to the invention enables the use of a luminaire designed for a typical light bulb. The invention also enables the reduction of the diameter of the portion of the self-ballasted fluorescent lamp near the base and the length of the lamp, the use of a socket designed for an incandescent lamp without any disagreeability, the reduction of production costs and the improvement of the appearance.